I have a dat(binary) file but i wish to convert this file into Ascii (txt) file using c++ but i am very new in c++ programming.so I juct opend my 2 files:myBinaryfile and myTxtFile but I don't know how to read data from that dat file and then how to write those data into new txt file.so i want to write a c+ codes that takes in an input containing binary dat file, and converts it to Ascii txt in an output file. if this possible please help to write this codes. thanks
Sorry for asking same question again but still I didn’t solve my problem, I will explain it more clearly as follows: I have a txt file called “A.txt”, so I want to convert this into binary file (B.dat) and vice verse process. Two questions:
1. how to convert “A.txt” into “B.dat” in c++
2. how to convert “B.dat” into “C.txt” in c++ (need convert result of the 1st output again into new ascii file)
my text file is like (no header):
1st line: 1234.123 543.213 67543.210 1234.67 12.000
2nd line: 4234.423 843.200 60543.232 5634.60 72.012
it have more than 1000 lines in similar style (5 columns per one line).
Since I don’t have experiences in c++, I am struggle here, so need your helps. Many Thanks
All files are just a stream of bytes. You can open files in binary mode, or text mode. The later simply means that it may have extra newline handling.
If you want your text file to contain only safe human readable characters you could do something like base64 encode your binary data before saving it in the text file.
Very easy:
Create target or destination file
(a.k.a. open).
Open source file in binary mode,
which prevents OS from translating
the content.
Read an octet (byte) from source
file; unsigned char is a good
variable type for this.
Write the octet to the destination
using your favorite conversion, hex,
decimal, etc.
Repeat at 3 until the read fails.
Close all files.
Research these keywords: ifstream, ofstream, hex modifier, dec modifier, istream::read, ostream::write.
There are utilities and applications that already perform this operation. On the *nix and Cygwin side try od, *octal dump` and pipe the contents to a file.
There is the debug utility on MS-DOS system.
A popular format is:
AAAAAA bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb cccccccccccccccc
where:
AAAAAA -- Offset from beginning of file in hexadecimal or decimal.
bb -- Hex value of byte using ASCII text.
c -- Character representation of byte, '.' if the value is not printable.
Please edit your post to provide more details, including an example layout for the target file.
Edit:
A complex example (not tested):
#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstdlib>
using namespace std;
const unsigned int READ_BUFFER_SIZE = 1024 * 1024;
const unsigned int WRITE_BUFFER_SIZE = 2 * READ_BUFFER_SIZE;
unsigned char read_buffer[READ_BUFFER_SIZE];
unsigned char write_buffer[WRITE_BUFFER_SIZE];
int main(void)
{
int program_status = EXIT_FAILURE;
static const char hex_chars[] = "0123456789ABCDEF";
do
{
ifstream srce_file("binary.dat", ios::binary);
if (!srce_file)
{
cerr << "Error opening input file." << endl;
break;
}
ofstream dest_file("binary.txt");
if (!dest_file)
{
cerr << "Error creating output file." << endl;
}
// While no read errors from reading a block of source data:
while (srce_file.read(&read_buffer[0], READ_BUFFER_SIZE))
{
// Get the number of bytes actually read.
const unsigned int bytes_read = srce_file.gcount();
// Define the index and byte variables outside
// of the loop to maybe save some execution time.
unsigned int i = 0;
unsigned char byte = 0;
// For each byte that was read:
for (i = 0; i < bytes_read; ++i)
{
// Get source, binary value.
byte = read_buffer[i];
// Convert the Most Significant nibble to an
// ASCII character using a lookup table.
// Write the character into the output buffer.
write_buffer[i * 2 + 0] = hex_chars[(byte >> 8)];
// Convert the Least Significant nibble to an
// ASCII character and put into output buffer.
write_buffer[i * 2 + 1] = hex_chars[byte & 0x0f];
}
// Write the output buffer to the output, text, file.
dest_file.write(&write_buffer[0], 2 * bytes_read);
// Flush the contents of the stream buffer as a precaution.
dest_file.flush();
}
dest_file.flush();
dest_file.close();
srce_file.close();
program_status = EXIT_SUCCESS;
} while (false);
return program_status;
}
The above program reads 1MB chunks from the binary file, converts to ASCII hex into an output buffer, then writes the chunk to the text file.
I think you are misunderstanding that the difference between a binary file and a test file is in the interpretation of the contents.
Related
Basically, I am trying to read binary data of a file by using fread() and print it on screen using printf(), now, the problem is that when it prints it out, it actually don't show it as binary 1 and 0 but printing symbols and stuff which I don't know what they are.
This is how I am doing it:
#include <stdio.h>
#include <windows.h>
int main(){
size_t sizeForB, sizeForT;
char ForBinary[BUFSIZ], ForText[BUFSIZ];
char RFB [] = "C:\\users\\(Unknown)\\Desktop\\hi.mp4" ; // Step 1
FILE *ReadBFrom = fopen(RFB , "rb" );
if(ReadBFrom == NULL){
printf("Following File were Not found: %s", RFB);
return -1;
} else {
printf("Following File were found: %s\n", RFB); // Step 2
while(sizeForB = fread(ForBinary, 1, BUFSIZ, ReadBFrom)){ // Step 1
printf("%s", ForBinary);
}
fclose(ReadBFrom);
}
return 0;
}
I would really appreciate if someone could help me out to read the actual binary data of a file as binary (0,1).
while(sizeForB = fread(ForBinary, 1, BUFSIZ, ReadBFrom)){
printf("%s", ForBinary); }
This is wrong on many levels. First of all you said it is binary file - which means there might not be text in it in the first place, and you are using %s format specifier which is used to print null terminated strings. Again since this is binary file, and there might not be text in it in the first place, %s is the wrong format specifier to use. And even if there was text inside this file, you are not sure that fread would read a "complete" null terminated string that you could pass to printf with format specifier %s.
What you may want to do is, read each byte form a file, convert it to a binary representation (google how to convert integer to binary string say, e.g., here), and print binary representation for each that byte.
Basically pseudocode:
foreach (byte b in FileContents)
{
string s = convertToBinary(b);
println(s);
}
How to view files in binary in the terminal?
Either
"hexdump -C yourfile.bin" perhaps, unless you want to edit it of course. Most linux distros have hexdump by default (but obviously not all).
or
xxd -b file
To simply read a file and print it in binary (ones and zeros), read it one char at a time. Then for each bit, print a '0' or '1'. Can print Most or Least significant bit first. Suggest MSb.
if (ReadBFrom) {
int ch;
while ((ch = fgetc(ReadBFrom)) != EOF) {
unsigned mask = 1u << (CHAR_BIT - 1); // CHAR_BIT is typically 8
while (mask) {
putchar(mask & ch ? '1' : '0');
mask >>= 1;
}
}
fclose(ReadBFrom);
}
I am writing a program that will read and write a file format that dictates the content of the file, byte by byte. The nature of this program is that the first two bytes details how many bytes are left in that part of the file, followed by another two bytes that indicates what the part of the file actually represents. This pattern is repeated for the length of the file. This means I have to write the exact numbers buffered by preceding zeros such that each component is the exact size it needs to be. I have written up a dummy file that illustrates my points:
#include <fstream>
#include <stdint.h>
int main() {
std::ofstream outputFile;
outputFile.open("test.txt",
std::ios::out | std::ios::ate | std::ios::binary);
const int16_t HEADER = 0x0002;
int16_t recordSize = 2*sizeof(int16_t);
int16_t version = 0x0258;
outputFile << recordSize << HEADER << version;
outputFile.close();
}
which writes a file named "test.txt" who's hex contents are:
34 32 36 30 30
and for those of us that can read straight hex this translates to:
42600
As you can see the preceding zeros are removed and my record is not what I was hoping it to be. Is there a way to use ofstream to buffer my numbers with zeros as I naively tried to do by using int16_t for all of the writes that I wanted to be exactly two bytes long? Is there another, possibly more stylistically correct way of doing this?
operator<< is for text formatting. You probably want to use .write() instead.
e.g.
outputFile.write(reinterpret_cast<char*>(&recordSize), sizeof(int16_t));
outputFile.write(reinterpret_cast<char*>(&HEADER), sizeof(int16_t));
// ...
I have 640*480 numbers. I need to write them into a file. I will need to read them later. What is the best solution? Numbers are between 0 - 255.
For me the best solution is to write them binary(8 bits). I wrote the numbers into txt file and now it looks like 1011111010111110 ..... So there are no questions where the number starts and ends.
How am I supposed to read them from the file?
Using c++
It's not good idea to write bit values like 1 and 0 to text file. The file size will bigger in 8 times. 1 byte = 8 bits. You have to store bytes, 0-255 - is byte. So your file will have size 640*480 bytes instead of 640*480*8. Every symbol in text file has size of 1 byte minimum. If you want to get bits, use binary operators of programming language that you use. To read bytes much easier. Use binary file for saving your data.
Presumably you have some sort of data structure representing your image, which somewhere inside holds the actual data:
class pixmap
{
public:
// stuff...
private:
std::unique_ptr<std::uint8_t[]> data;
};
So you can add a new constructor which takes a filename and reads bytes from that file:
pixmap(const std::string& filename)
{
constexpr int SIZE = 640 * 480;
// Open an input file stream and set it to throw exceptions:
std::ifstream file;
file.exceptions(std::ios_base::badbit | std::ios_base::failbit);
file.open(filename.c_str());
// Create a unique ptr to hold the data: this will be cleaned up
// automatically if file reading throws
std::unique_ptr<std::uint8_t[]> temp(new std::uint8_t[SIZE]);
// Read SIZE bytes from the file
file.read(reinterpret_cast<char*>(temp.get()), SIZE);
// If we get to here, the read worked, so we move the temp data we've just read
// into where we'd like it
data = std::move(temp); // or std::swap(data, temp) if you prefer
}
I realise I've assumed some implementation details here (you might not be using a std::unique_ptr to store the underlying image data, though you probably should be) but hopefully this is enough to get you started.
You can print the number between 0-255 as the char value in the file.
See the below code. in this example I am printing integer 70 as char.
So this result in print as 'F' on the console.
Similarly you can read it as char and then convert this char to integer.
#include <stdio.h>
int main()
{
int i = 70;
char dig = (char)i;
printf("%c", dig);
return 0;
}
This way you can restrict the file size.
Just wondering, if I read a PNG file as a binary file, and I know how to write the hex numbers into another plain txt or whatever file, then how can I recreate the PNG file with those hex numbers?
This is the code I use to read from a PNG file and write to another plain txt file:
unsigned char x;
ifile.open("foo.png",ios::binary);
ifile>>noskipws>>hex;
while(ifile>>x){
ofile<<setw(2)<<setfill('0')<<(int)x;
//do some formatting stuff to the ofile, ofile declaration omitted
//some ifs to see if IEND is read in, which is definitely correct
//if IEND, break, so the last four hex numbers in ofile are 49 45 4E 44
}
//read another 4 bytes and write to ofile, which are AE 42 60 82, the check sum
The reason why I am doing this is because I have some PNG files which have some irrelevant messages after IEND chunk, and I want to get rid of them and only keep the chunks related to the actual picture and split them into different files. By "irrelevant messages" I mean they are not the actual part of the picture but I have some other use with them.
It's easy, you just need to read every 2 characters and convert them from hex back to binary.
unsigned char x;
char buf[3] = {0};
ifile.open("foo.hex");
while(ifile>>buf[0]>>buf[1]){
char *end;
x = (unsigned char) strtol(buf, &end, 16);
if (*end == 0) // no conversion error
// output the byte
I am unclear about how reading long integers work. If I say
long int a[1]={666666}
ofstream o("ex",ios::binary);
o.write((char*)a,sizeof(a));
to store values to a file and want to read them back as it is
long int stor[1];
ifstream i("ex",ios::binary);
i.read((char*)stor,sizeof(stor));
how will I be able to display the same number as stored using the information stored in multiple bytes of character array?
o.write does not write character, it writes bytes (if flagged with ios::binary). The char-pointer is used because a char has length 1 Byte.
o.write((char*)a,sizeof(a));
(char*) a is the adress of what o.write should write. Then it writes sizeof(a) bytes to a file. There are no characters stored, just bytes.
If you open the file in a Hex-Editor you would see something like this if a is int i = 10:
0A 00 00 00 (4 Byte, on x64).
Reading is analogue.
Here is a working example:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main (int argc, char* argv[]){
const char* FILENAM = "a.txt";
int toStore = 10;
ofstream o(FILENAM,ios::binary);
o.write((char*)&toStore,sizeof(toStore));
o.close();
int toRestore=0;
ifstream i(FILENAM,ios::binary);
i.read((char*)&toRestore,sizeof(toRestore));
cout << toRestore << endl;
return 0;
}
Sorry I took so long to see your question.
I think the difference between binary is the binary will read and write the file as is. But the non-binary (i.e. text) mode will fix up the end-of-line '\n' with carriage-return '\r'. The fix-up will change back and forth between '\n' and '\r', or "\n\r" or "\r\n" or leave it as '\n'. What it does depends on whether the target operating system is Mac, Windows, Unix, etc.
I think if you are reading and writing an integer, it will read and write your integer fine and it will look correct. But if some byte(s) of the integer look like '\r' and '\n', then the integer will not read back correctly from the file.
Binary assures that reading back an int will always be correct. But you want text mode to format a file to be read in a text editor such as Windows's Notepad.